JP2003261908A - Snow melting equipment - Google Patents

Abstract

(57) [Abstract] [Problem] To improve the heat storage efficiency and improve the snow melting ability. SOLUTION: An underground ground heat exchanger 2 for exchanging heat medium L with a ground heat and a radiator 1 installed on a snowfall surface portion of a snow melting target.
A heat medium circulating path 3 for circulating the heat medium L by a circulation pump 4 is provided between the heat pump and a snowfall surface temperature sensor 5 for detecting the temperature tr of the snowfall surface portion, and the snowfall surface temperature sensor 5
In the snow melting facility provided with the control means 8 for controlling the start and stop of the circulation pump 4 in accordance with the detected temperature tr, the control means 8 is set to two set temperatures of a snow melting threshold temperature tws and a heat storage threshold temperature tss higher than that. On the other hand, when the detection temperature tr of the snowfall surface temperature sensor 5 is equal to or lower than the snow melting threshold temperature tws, and when the detection temperature tr of the snowfall surface temperature sensor 5 is equal to or higher than the heat storage threshold temperature tss, the circulating pump 4 is operated, and The circulation pump 4 is stopped when the temperature tr detected by the temperature sensor 5 is higher than the snow melting threshold temperature tws and lower than the heat storage threshold temperature tss.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snow melting facility, and more specifically, it is provided with a circulation pump between a ground-embedded heat exchanger for exchanging heat medium to ground and a radiator installed on a snowfall surface of a snowmelt target. A heating medium circulation path for circulating a heating medium is provided, and a snowfall surface temperature sensor for detecting the temperature of the snowfall surface portion, and a control means for controlling start / stop of the circulation pump according to the detected temperature of the snowfall surface temperature sensor. Regarding snow melting equipment to be provided.

[0002]

2. Description of the Related Art In this type of snow melting equipment, in addition to winter snow melting operation in which ground heat is collected by a heat exchanger to ground and the collected heat is radiated by a radiator by circulating heat medium by operating a circulation pump, In the same season or summer, there is a system in which a heat storage operation is performed in which a heat radiator circulates by operating a circulation pump to collect ambient heat with a radiator and store the collected heat in the ground with a ground heat exchanger. However, conventionally, in order to selectively perform the snow melting operation and the heat storage operation, the following configuration has been adopted.

That is, the snow-melting operation mode and the heat storage operation mode are switched and the threshold temperature is switched by an artificial switching operation or automatic switching based on a time schedule, and the temperature detected by the snow surface temperature sensor is changed. As the start / stop control of the circulation pump by the corresponding control means, in the snow melting operation mode, with respect to the switching threshold temperature at that time (a low threshold temperature as a reference for necessity of snow melting),
When the temperature detected by the snow surface temperature sensor is below the threshold temperature, the circulation pump is operated to perform the snow melting operation, and when the temperature detected by the snow surface temperature sensor is higher than the threshold temperature, the circulation pump is stopped. On the other hand, in the heat storage operation mode, conversely, the circulation pump is operated when the temperature detected by the snow surface temperature sensor is higher than the threshold temperature for switching (high temperature threshold value for heat storage). The heat storage operation was performed, and the circulation pump was stopped when the temperature detected by the snow surface temperature sensor was below the threshold temperature.

[0004]

However, in the above-mentioned conventional equipment, even if the heat storage operation becomes possible due to a warm day in the winter when the snowmelt operation mode is switched to, the threshold temperature can be switched. If the switching from the snow-melting operation mode to the heat-storage operation mode is not performed, the heat-storage operation is not performed, and this causes the heat storage efficiency throughout the year to be limited to a low level, resulting in a problem that the snow-melting ability becomes low. there were.

In view of this situation, the main problem of the present invention is to
The problem is effectively solved by adopting a rational control mode for the start / stop control of the circulation pump.

[0006]

SUMMARY OF THE INVENTION [1] The invention according to claim 1 relates to a snow melting facility, which is characterized in that a ground-to-ground heat exchanger for exchanging heat of a heat medium with the ground and a snowfall surface portion of a snow melting target. A heat medium circulation path that circulates a heat medium with a circulation pump is provided between the installed radiator and a snow surface temperature sensor that detects the temperature of the snow surface, and according to the detected temperature of the snow surface temperature sensor. In a configuration in which a control means for controlling the start and stop of the circulation pump is provided, the control means controls the detected temperature of the snowfall surface temperature sensor with respect to two set temperatures of a snow melting threshold temperature and a heat storage threshold temperature higher than that. When the snow melting threshold temperature or less, and, when the detected temperature of the snow surface temperature sensor is equal to or higher than the heat storage threshold temperature, operating the circulation pump, and,
When the temperature detected by the snow surface temperature sensor is higher than the snow melting threshold temperature and lower than the heat storage threshold temperature, the circulation pump is stopped.

In other words, according to this configuration, it is not necessary to switch between the snow-melting operation mode and the heat storage operation mode as described above by artificial switching operation or automatic switching based on a time schedule, and without changing the threshold temperature. If the temperature detected by the snow surface temperature sensor falls below the snow melting threshold temperature as the snow melting necessity criterion throughout the season, the circulation pump is operated to perform the snow melting operation, and the temperature detected by the snow surface temperature sensor is stored as heat. When the heat storage threshold temperature as the necessity criterion is reached or higher, the circulation pump is similarly operated to perform the heat storage operation.

When the detected temperature of the snow surface temperature sensor is higher than the snow melting threshold temperature and lower than the heat storage threshold temperature, it is determined that snow melting is not necessary and heat cannot be stored, the circulation pump is stopped and the snow melting operation and heat storage are performed. Both the driving and the dormant state.

Therefore, according to the above-mentioned structure of the invention according to claim 1, the heat storage operation can be surely performed when the heat storage operation becomes possible not only in the summer but also in the winter and the intermediate seasons. Compared with the above-mentioned conventional equipment, the heat storage efficiency throughout the year can be effectively increased, and the snow melting capacity is effectively improved accordingly.

[2] The invention according to claim 2 specifies a preferred embodiment for carrying out the invention according to claim 1, which is characterized by the inlet heat medium temperature and outlet of the ground heat exchanger. A heating medium temperature sensor for detecting the heating medium temperature is provided, and the control means is configured to set a lower limit of the subtraction temperature value obtained by subtracting the outlet heating medium temperature detected by the heating medium temperature sensor from the inlet heating medium temperature detected by the heating medium temperature sensor. When the value is smaller than the value, the circulation pump is not operated when the temperature detected by the snow surface temperature sensor is equal to or higher than the heat storage threshold temperature.

That is, in the heat storage operation, the ground around the ground heat exchanger is in a saturated heat storage state (that is, the ground temperature around the ground heat exchanger rises up to near the inlet heat medium temperature of the ground heat exchanger and the The heat transfer medium temperature at the outlet of the ground heat exchanger gradually rises and approaches the heat transfer medium temperature at the inlet of the ground heat exchanger.

Therefore, as described above, when the subtraction temperature value obtained by subtracting the detection outlet heat medium temperature from the detection inlet heat medium temperature of the ground heat exchanger is smaller than the set lower limit value, the detected temperature of the snow surface temperature sensor is If the circulation pump operation (that is, heat storage operation) when the temperature is higher than the threshold temperature is not performed, the temperature detected by the snow surface temperature sensor will increase even if the ground around the heat exchanger is already in a saturated heat storage state. It is possible to reliably avoid unnecessary heat storage operation by operating the circulation pump unnecessarily just because the temperature is equal to or higher than the heat storage threshold temperature, which effectively prevents waste of pump power. can do.

In the practice of the invention according to claim 1, the lower the heat storage threshold temperature is set, the more frequently the heat storage operation is performed, and more heat can be stored in the winter and the intermediate seasons, but in the summer. If the threshold temperature of heat storage is relatively low in a situation where the underground temperature is high, such as in the middle season near the summer
Once the temperature detected by the snow surface temperature sensor rises and the circulation pump starts operating and the heat storage operation is performed,
Even if it becomes necessary to stop the heat storage operation after that, the high temperature heat accumulated in the ground is radiated to the snow surface by the heat medium circulation, and the temperature detected by the snow surface temperature sensor is The temperature is kept above the threshold temperature, which may cause not only the waste heat storage operation to be continued unnecessarily, but also wasteful consumption of the heat stored in the ground. According to the above-described configuration of the invention, the operation of the circulation pump can be reliably stopped and the heat storage operation can be ended by the decrease in the subtraction temperature value before such a situation.

That is, from this point as well, it is possible to effectively prevent waste of pump power due to useless heat storage operation, and to set the heat storage threshold temperature to a low value so that the heat storage amount in the winter and the intermediate seasons. It is possible to increase the heat storage efficiency and prevent the wasteful consumption of heat stored in the ground as described above, so that the heat storage efficiency throughout the year can be more effectively increased.

[3] The invention according to claim 3 specifies a preferred embodiment for carrying out the invention according to claim 1 or 2, which is characterized in that the control means is provided to change the underground temperature. The configuration is such that the heat storage threshold temperature is changed according to the above.

That is, as described above, in the practice of the invention according to claim 1, as the heat storage threshold temperature is set lower, more heat can be stored in the winter and the middle seasons, but in the middle of the summer and the summer. If the heat storage threshold temperature is relatively low in a situation where the underground temperature is high, such as the season, the temperature detected by the snow surface temperature sensor will be equal to or higher than the heat storage threshold temperature due to the release of high temperature heat accumulated in the ground under conditions where the heat storage operation should normally be stopped. Is held in
This may lead to a situation in which the heat storage operation is unnecessarily continued to wastefully consume the heat stored in the ground, but as described above, the setting of the heat storage threshold temperature is changed according to the change in the ground temperature. By doing so, in a situation where the underground temperature is low, such as in the winter and intermediate seasons, where there is no risk of causing the above situation, the heat storage threshold temperature is lowered to allow more heat to be stored, while in the summer or In situations where the above-mentioned situation may occur in situations where the underground temperature is high, such as in the mid-season near summer, the heat storage threshold temperature is raised to wasteful continuation of heat storage operation and wasteful consumption of heat stored in the ground. Can be prevented.

That is to say, this makes it possible to effectively prevent waste of pump power due to wasteful heat storage operation, as in the case of the second aspect of the invention, and also more effective heat storage efficiency throughout the year. Can be increased to

In order to change the setting of the heat storage threshold temperature according to the change of the underground temperature, a method of changing the heat storage threshold temperature based on the time schedule according to the change data of the underground temperature or a sensor is used. Various changing methods such as a method of changing the setting of the heat storage threshold temperature based on the detected underground temperature can be adopted.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a snow melting facility on a sidewalk.
Is a radiator installed under the road surface of the sidewalk R (that is, a snowfall surface part of the snowmelt target), 2 is a ground heat exchanger buried in the underground G,
Reference numeral 3 is a heat medium circulation path for circulating the heat medium L (for example, brine or water) between the radiator 1 and the ground heat exchanger 2 by the circulation pump 4.

Reference numeral 5 is a snow surface temperature sensor for detecting a road surface temperature tr of a radiator installed portion on the sidewalk R, and 6 is an inlet heat medium temperature ti of the ground heat exchanger 2 (in other words, an outlet of the radiator 1). The heat medium temperature sensor on the return side for detecting the heat medium temperature, 7 is the heat medium temperature on the forward side for detecting the outlet heat medium temperature to of the ground heat exchanger 3 (in other words, the inlet heat medium temperature of the radiator 1) Reference numeral 8 denotes a sensor, and reference numeral 8 denotes a controller that controls the start / stop of the circulation pump 4 based on the detection information of these sensors 5-7.

The controller 8 is configured to control the start / stop of the circulation pump 4 as shown in (a) to (n) below (see FIGS. 2 and 3).

(A) After the first timer is reset (# 1), the detected temperature tr of the road surface temperature sensor 5 is equal to the heat storage threshold temperature t.
It is determined whether or not it is ss or more (# 2).

(B) When the temperature tr detected by the road surface temperature sensor 5 is equal to or higher than the heat storage threshold temperature tss in this determination, the first
The time measurement by the timer is started (# 3), and subsequently, it is judged whether or not there is a pump failure based on the diagnostic result of the diagnostic system (# 4), and the heat is detected based on the heat medium pressure detected by the pressure sensor. It is determined whether or not there is an abnormal pressure drop due to medium leakage (# 5).

(C) If there is no abnormality in the determination of the pump failure or the abnormal pressure drop, the circulation pump 4 is operated (# 6). That is, when the temperature tr detected by the road surface temperature sensor 5 is equal to or higher than the heat storage threshold temperature tss, the circulation pump 4 is operated to circulate the heat medium, whereby the radiator 1
Then, the heat storage operation is performed in which heat is collected from the side of the sidewalk R and the collected heat is stored in the surrounding ground G by the ground heat exchanger 2.

(D) Then, the measurement time T of the first timer
It is determined whether or not a has reached the set time Tas (for example, 20 minutes) (# 7), and if the measured time Ta of the first timer has reached the set stabilization time Tas, the heat medium temperature sensor 6 on the return side is used. It is determined whether or not the subtraction temperature value Δtio obtained by subtracting the detection outlet heat medium temperature to by the upstream heat medium temperature sensor 7 from the detected inlet heat medium temperature ti is equal to or more than the set lower limit value tms (# 8). If the measured time Ta of the first timer has not reached the set stabilization time Tas, the process returns and the first
It waits until the measured time Ta of the timer reaches the set stabilization time Tas.

(E) Then, determination of subtraction temperature value (# 8)
If the subtraction temperature value Δtio is equal to or higher than the set lower limit value tms, the flow returns, the detected temperature tr of the road surface temperature sensor 5 is equal to or higher than the heat storage threshold temperature tss, there is no pump failure and abnormal pressure drop, and the subtraction temperature value Δtio is set. The heat storage operation by the circulation pump operation is continued on condition that the lower limit value tms or more is satisfied. If there is no abnormality in the pump failure determination (# 4) or the abnormal pressure drop determination (# 5), the circulation pump 4 is stopped (# 9) and the process returns.

(F) On the other hand, in the judgment of the subtraction temperature value (# 8), if the subtraction temperature value Δtio is less than the set lower limit value tms,
Assuming that the underground G around the ground heat exchanger 2 has reached the saturated heat storage state, the circulation pump 4 is stopped (# 10) to end the heat storage operation, and then the first and second timers are reset (# 1).
1), start of time measurement by the second timer (# 12),
Waiting process to wait until the measurement time Tb of the second timer reaches the set leaving time Tbs (time to wait for the ground G around the heat exchanger 2 to return to the unsaturated heat storage state by natural heat dissipation, for example, 20 minutes) ( Return through # 13).

In contrast to the above heat storage operation side control, in the determination (# 2) as to whether the detected temperature tr of the road surface temperature sensor 5 is the heat storage threshold temperature tss or more, the detected temperature tr of the road surface temperature sensor 5 is If the heat storage threshold temperature tss is less than,
It is determined whether the detected temperature tr of the road surface temperature sensor 5 is equal to or lower than the snow melting threshold temperature tws (# 14). When the detected temperature tr of the road surface temperature sensor 5 is higher than the snow melting threshold temperature tws in this determination, the circulation pump 4 is used. Returning after the stop operation (# 9), the detected temperature tr of the road surface temperature sensor 5 is lower than the heat storage threshold temperature tss and higher than the snow melting threshold temperature tws,
As a situation where heat storage is not possible and snow melting is not necessary, the circulation pump 4 is kept in a stopped state and both the heat storage operation and the snow melting operation are stopped.

(H) On the other hand, it is judged whether the detected temperature tr of the road surface temperature sensor 5 is equal to or lower than the snow melting threshold temperature tws (# 14).
Therefore, the detected temperature tr of the road surface temperature sensor 5 is the snow melting threshold temperature tw.
If it is s or less, as the control on the snow melting operation side, first, it is judged whether or not there is a pump failure based on the diagnosis result of the diagnosis system (# 15), and the heat medium is detected based on the heat medium pressure detected by the pressure sensor. It is determined whether or not there is an abnormal pressure drop due to leakage (# 16).

(I) If there is no abnormality in the determination of the pump failure or the abnormal pressure drop, the circulation pump 4 is operated (# 17). That is, the road surface temperature sensor 5
By operating the circulation pump 4 to circulate the heat medium under the condition that the detected temperature tr of the temperature is equal to or lower than the snow melting threshold temperature tws, the ground heat exchanger 2 collects heat from the surrounding ground G and the collected heat is radiated. Carry out snow melting operation to radiate heat in 1.

(E) After returning, the snow melting operation by the circulation pump operation is continued on condition that the detected temperature tr of the road surface temperature sensor 5 is equal to or lower than the snow melting threshold temperature tws and there is no pump failure or abnormal pressure drop. If there is no abnormality in the pump failure determination (# 15) or the abnormal pressure drop determination (# 16), the circulation pump 4 is stopped (# 9) and then returned as in the heat storage operation. .

Next, the heat storage threshold temperature tss, which is a criterion for the heat storage operation, will be described.
In addition to the pump start / stop control of (n), the setting of the heat storage threshold temperature tss is automatically changed according to the time schedule shown in FIG. 4, and in this time schedule, the underground temperature becomes high. The target change value of the heat storage threshold temperature tss is set according to the seasonal change of the underground temperature so that the heat storage threshold temperature tss becomes higher at certain times.

That is, the lower the heat storage threshold temperature tss is set, the more frequently the heat storage operation is performed, and more heat can be stored in the winter and the middle seasons. When the heat storage threshold temperature tss is relatively low in a situation where the road surface temperature sensor 5
When the operation of the circulation pump 4 is started and the heat storage operation is carried out due to the detection temperature tr becoming higher, even if the heat storage operation becomes impossible after that and the heat storage operation needs to be stopped,
On the contrary, the high temperature heat accumulated in the ground G is radiated from the radiator 1 to the road surface of the sidewalk R by the heat medium circulation, so that the detected temperature tr of the road surface temperature sensor 5 is maintained at the heat storage threshold temperature tss or more. Therefore, not only the heat storage operation is unnecessarily continued, but also the heat stored in the underground G is consumed wastefully.

On the other hand, in the snow melting equipment of this embodiment,
As described above, the heat storage threshold temperature ts is changed according to the seasonal change of the underground temperature.
By changing the setting of s, and when the subtraction temperature value Δtio becomes less than the set lower limit value tms in the pump start / stop control, the circulation pump 4 is stopped and the heat storage operation is ended, so that the above-described situation occurs. While surely preventing this, it will be possible to store as much heat as possible in winter and intermediate season when the ground temperature is low.

Further, in the heat storage operation, when the subtraction temperature value Δtio becomes less than the set lower limit value tms, the circulation pump 4 is stopped. Therefore, wasteful heat storage operation in the saturated heat storage state is avoided and pump power is reduced. It also prevents waste of money.

[Other Embodiments] In the above embodiment, in a situation where the subtraction temperature value Δtio obtained by subtracting the detection outlet heat medium temperature to from the detection inlet heat medium temperature ti of the ground heat exchanger 2 is smaller than the set lower limit value tms, The invention according to claim 2, wherein the circulation pump operation is not executed when the detected temperature tr of the road surface temperature sensor 5 (snow surface temperature sensor) is equal to or higher than the heat storage threshold temperature tss,
An example has been shown in which the heat storage threshold temperature tss is set and changed in accordance with the change in the underground temperature, and the invention according to claim 3 is carried out in parallel.
Only one of these may be implemented.

The heat storage threshold temperature tss corresponding to the change in the underground temperature
When changing the setting, the heat storage threshold temperature tss is changed based on the time schedule according to the underground temperature change data as in the above-described embodiment, and the heat storage threshold temperature is detected based on the ground temperature detected by the sensor. A method of changing the setting of the temperature tss may be adopted, and various methods can be adopted as the changing method.

The specific structures of the ground heat exchanger 2 buried in the ground G and the radiator 1 installed on the snowfall surface of the snow melting target are not limited to the structures shown in the above-mentioned embodiments, but various structures are available. The configuration can be changed.

The object of snow melting is not limited to the sidewalk R, but may be any place such as a roadway, a plaza or an outdoor staircase.

[Brief description of drawings]

FIG. 1 is a perspective view showing the entire structure of a snow melting facility.

FIG. 2 is a graph illustrating a control mode of pump start / stop control.

FIG. 3 is a control flowchart.

[Figure 4] Thermal storage threshold temperature

[Explanation of symbols]

1 radiator 2 Ground heat exchanger 3 Heat medium circuit 4 circulation pumps 5 Snowfall surface temperature sensor 6,7 Heat medium temperature sensor 8 Control means L heat medium ti Temperature of inlet heat medium of ground heat exchanger to Heat exchanger outlet heat medium temperature tr Temperature of snow surface tms lower limit value tss heat storage threshold temperature tws snow melting threshold temperature Δtio Subtraction temperature value

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Claims (3)

[Claims] 1. A heat medium circulation path for circulating a heat medium by a circulation pump is provided between a ground-embedded heat exchanger for exchanging heat with the ground and a radiator installed on a snowfall surface of a snowmelt target. A snow-melting surface temperature sensor for detecting the temperature of the snow-falling surface part, and a snow-melting facility provided with a control means for controlling the start and stop of the circulation pump according to the detected temperature of the snow-falling surface temperature sensor, wherein the control means is With respect to two set temperatures of a snow melting threshold temperature and a heat storage threshold temperature higher than that, when the detected temperature of the snow surface temperature sensor is equal to or lower than the snow melting threshold temperature, and when the detected temperature of the snow surface temperature sensor is the heat storage threshold value. A snow melting facility configured to operate the circulation pump when the temperature is equal to or higher than a temperature, and to stop the circulation pump when a temperature detected by the snowfall surface temperature sensor is higher than a snow melting threshold temperature and lower than a heat storage threshold temperature. 2. A heat medium temperature sensor for detecting an inlet heat medium temperature and an outlet heat medium temperature of the ground heat exchanger is provided, and the control means controls the heat medium temperature from the inlet heat medium temperature detected by the heat medium temperature sensor. When the subtraction temperature value obtained by subtracting the outlet heat medium temperature detected by the temperature sensor is smaller than the set lower limit value, the circulation pump operation is not performed when the temperature detected by the snow surface temperature sensor is equal to or higher than the heat storage threshold temperature. The snow melting equipment according to claim 1. 3. The snow melting equipment according to claim 1, wherein the control means is configured to change the setting of the threshold temperature for heat storage in accordance with a change in underground temperature.